In automotive vehicles, it is common to have a climate control system located within an instrument panel which provides heated or cooled air to occupants through dash panel defrost air outlets, instrument panel venting air outlets and floor directed air outlets. These traditional climate control systems often include a heater core that performs heat exchange between the engine coolant, which is heated by the engine, and the cool air in the cabin/outside environment, in order to provide warm air to the passenger compartment. Some vehicles include an air conditioning system that cooperates with an evaporator for absorbing heat from the air in the vehicle. The heater core and evaporator are typically provided in an HVAC case located in the passenger compartment of the vehicle.
In some vehicles, the climate control system is adapted to control three zones of the cabin space. Generally, the three zones include the driver's side, the passenger's side and the rear occupant zone. The HVAC case typically includes ducting to accommodate air distribution to these appropriate zones as desired. The heater core is generally disposed downstream of a fan for communicating warmed air into the passenger compartment.
A heater core typically does not produce uniform temperature distribution across its plane due, in part, to placement of the water inlet. As a result, a temperature gradient is observed along the heater core. With a three zone HVAC configuration, sometimes an undesirable temperature imbalance is observed between the driver and the passenger sides of the case. Conventional methods to compensate for the temperature imbalance are to increase tank depth of the heater core, increase thickness of the heater core, or shift the entire heater core to one side of the case. All of these options involve costly tooling changes and can have a negative impact in terms of airflow volume and noise.